The present disclosure relates generally to leak detection, and in particular, to use of acoustic profile recognition in discriminating between hazardous emissions and non-hazardous emissions.
Acoustic technology for detection of leaks (e.g., gas leaks) in hazardous locations has been commercially available for over a decade. Much of the advancement with acoustic leak detection has been focused on discriminating between an actual gas leak and potential false sources of acoustic noise in the frequency range of interest (e.g., ultrasonic frequencies). While conventional acoustic detection can provide very good discrimination between pressurized gas leaks and false positives, there is a real and un-met industry need to provide discrimination between hazardous emissions and non-hazardous emissions. A non-hazardous emission may be an escape of pressurized gas that occurs during normal plant operations or as part of maintenance, start-up, or shut down procedures. Sources of non-hazardous emission can be overpressure valves, flare stacks, shop air and emergency shutdown release. These non-hazardous emissions are actual pressurized gas escapes, can be very large in magnitude, and will be detected as an alarm condition by conventional acoustic detectors. Ideally, an acoustic detector would be able to distinguish between hazardous and non-hazardous emissions, however common practice is to either increase the alarm threshold, or physically move the detector away from the source of the non-hazardous emission to avoid an alarm. Both of these practices de-sensitize the detector to hazardous emissions in the same vicinity. Also, some of the non-hazardous emissions can be of significant duration, making the adjustment to a longer alarm time threshold impractical.